"Pete Snell" wrote in message
...
Nick Mueller wrote:
Martin H. Eastburn wrote:

Another method - friction heat. Put a short length of drill rod and
round
it over with a file - and then use it to heat a spot. Get the spot red.


I tried that trick several times, but only failed. What's the trick
behind
the trick?


Nick

I've used that trick to drill a hole in bandsaw blade stock, but we
just used a plain old common nail. My understanding was that it combined
annealing the spot, along with 'sucking' a bit of the carbon outta the saw
blade into the lower carbon steel nail. Not sure if that's why it worked,
but it did.

I'd be skeptical about the nail sucking out carbon, unless your nails really
suck to begin with. But the technique works well on plain-carbon and
case-hardened simple alloys. On slower-quenching alloys it may not work at
all. It may, in fact, make things worse.

This is a common gunsmith method for drilling holes for a 'scope mount on
vintage Springfield '03 receivers. They were case-hardened and harder than
the hammers of hell.

--
Ed Huntress